Fuel cell systems heretofore have used drain valves for controlling the draining of water to a drain. A problem arises when the fuel cell system shuts down under ambient freezing conditions. Water frozen on the valve seat may cause the valve not to open and/or close properly, and thereby interfere with proper operation of the system.
According to U.S. Published Patent Application No. 2007/0141419, heating wires heretofore have been wound around the drain valves thereby to heat the valve prior to re-start of the fuel cell system. This was considered undesirable because of the requirement for additional heating means to thaw ice in the drain valve and the substantial amount of thawing time and thawing power needed. The solution set forth in said published patent application was to improve the draining ability of the valve by providing a valve structure comprising an inlet pipe having an elliptical valve seat, an outlet pipe parallel to the inlet pipe, and a valve body connecting the inlet pipe and outlet pipe such that the inlet pipe is in communication with the outlet pipe, with the valve body being inclined with respect to the inlet pipe at a predetermined angle.